PROJECTSUMMARY. Ankyrinproteins,ankyrin-R(ANK1),ankyrin-B(ANK2),andankyrin-G(ANK3),referredtoasAnkR, AnkB,andAnkGrespectively,arefoundthroughoutthebodyandactastheprimarylinkbetweenthespectrin- basedcytoskeletonandthecytoplasmicdomainofmanymembrane-associatedproteinsthroughtheir conserved24ANKrepeats.AlthoughAnkGandAnkBarewellrecognizedasimportantdomainorganizers withinthenervoussystem,fewstudieshaveinvestigatedAnkR?srole.Instead,researchintothefunctionof AnkRhaspredominatelyfocusedonitsfunctioninerythrocyteswhereitcreatesstructuralstabilityby anchoringBand3toIspectrin2,withmutationsinAnkRresultinginseverespherocyticanemia.Interestingly though,ourlabrecentlyshowedAnkRcancompensateforalossofAnkGandclusterNa+channelsatnodes ofRanvier,suggestinganeurologicalrole.Additionally,multiplestudieshaveindicatedvariousneurological disturbanceshavedisruptionsinAnkR,includingcerebellardysfunctionandAlzheimer?s disease.Yetstill,theexpressionprofile,consequencesofdisruption,andinteractingproteinsof AnkRinthenervoussystemremainpoorlyunderstood.Ihypothesizethattheankyrinfamilyofproteinsplay complementary,butdistinctrolesinthebrainwheretheytethertransmembraneproteinstothespectrin cytoskeleton.Theobjectivesproposedare:toelucidateAnkR?sexpressionpatterns,functions,andmolecular interactionsinthebrain.Aim1willdeterminethetemporalandspatialexpressionofAnkRinthebrain.By analysisofAnkRthroughpostnataldevelopmentIwillestablishthetemporal,spatial,andcell-typespecific expression.Aim2willdeterminethecellularandbehavioralconsequencesofdisruptionofAnkRthrough analysisofanewAnkRconditionalknockoutmousemodel,whichallowsneuronalpopulationsofcellstobe studied,whilesparingerythroctes.ExaminationofphenotypeswillyieldkeyinsightsintoAnkRfunctioninthe nervoussystem.Aim3willdeterminethecytoskeletalandmembraneproteinsAnkRinteractswithinthe nervoussystem.Thiswillrevealthenormalproteinfunctionaswellasmechanisticinsightintothephenotypes resultingfromloss.CompletionofthesestudieswillrevealthefunctionofAnkRinthebrain,andenhanceour understandingofthemolecularmechanismsgoverningregionalproteinorganizationinthedeveloping,aging, anddiseasedbrain.BycomparingwhatIlearnaboutaboutAnkRtoAnkGandAnkB,Iwillresolvethe hypothesistoconcludeifAnkRfunctionsredundantly,orhasauniqueneuronalfunction.Moreover,data gainedfromtheseexperimentsmayalsoexplainAnkR?sroleinneurologicalconditionssuchasAlzheimer?s disease(AD),schizophrenia,andcerebellardysfunctioninwhichderegulationofAnkRhasbeenproposed.In total,completionoftheproposedexperimentswilldeterminetheroleofAnkRinnormalbrainfunction.